title: Trehalose is not a universal solution for solid lipid nanoparticles freeze-drying.
abstract: OBJECTIVE
  To prepare stable and easy to handle formulation of solid lipid nanoparticles (SLNs) by freeze-drying with or without cryoprotectants, as appropriate.
  
  
  METHODS
  SLNs were freeze-dried without cryoprotectants or with cryoprotectants in quantities selected by freeze-thaw test (sucrose, glucose) or literature search (trehalose, maltose). Appearance, re-dispersability and size distribution of re-dispersed samples were evaluated.
  
  
  RESULTS
  SLN could be freeze-dried using 10% sucrose, trehalose or maltose. Trehalose was effective in protecting one of presented formulations that was already very stable on its own; its efficiency in protecting other two formulations was limited.
  
  
  CONCLUSIONS
  Our results are in line with various reports of successful freeze-drying of SLN, but considering the stability of original dispersions, no improvement was achieved.
  
  
  CONCLUSIONS
  We confirmed that trehalose is among the most suitable cryoprotectant for SLN, however it did not improve shelf-life of the most stable formulation.
authors.affiliation: Institute of Biotechnology and Bioengineering, Centre of Genomics and Biotechnology, University of Trás-os-Montes and Alto Douro (IBB/CGB-UTAD) , Vila-Real , Portugal .
authors.forename: Slavomira
authors.initials: S
authors.lastname: Doktorovova
authors.forename: Ranjita
authors.initials: R
authors.lastname: Shegokar
authors.forename: Lisete
authors.initials: L
authors.lastname: Fernandes
authors.forename: Paula
authors.initials: P
authors.lastname: Martins-Lopes
authors.forename: Amélia M
authors.initials: AM
authors.lastname: Silva
authors.forename: Rainer H
authors.initials: RH
authors.lastname: Müller
authors.forename: Eliana B
authors.initials: EB
authors.lastname: Souto
mesh_terms: D003451:Cryoprotective Agents / Q000737:chemistry*; D005612:Freeze Drying / Q000379:methods*; D008055:Lipids / Q000737:chemistry*; D008320:Maltose / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D012995:Solubility; D013395:Sucrose / Q000737:chemistry; D014199:Trehalose / Q000737:chemistry*
chemical_list: D003451:Cryoprotective Agents; D008055:Lipids; D013395:Sucrose; D008320:Maltose; D014199:Trehalose